• Specimen Number

  19

• Description

  Rough-quarried block of gray-pink granite showing mainly gray quartz and  pink alkali feldspars. Close up shows minor gneissic layering in quartz with altered mafic minerals.

• Classification

  Igneous. Plutonic. Granitic. Granite. Pink.

• Location & Occurrence

  Identified by Massachusetts survey as  the Milford, Chelmsford, or Quincy Granite, likely from either Gloucester or Rockport.   USGS Describes the Chemsford granite as a medium-grained, often gneissic, muscovite-bearing granite, which matches this specimen.  It was one of many synorogenic intrusives during the Acadian Orogeny.

• Geologic Age Lower Devonian, roughly 390 Ma +/-.
• Geoheritage Granite like this was quarried widely in eastern Ma. Our specimen (#19), if it's the Quincy Granite, was associated with Bunker Hill Monument and the first railroad in the U.S., dating to 1826.
• Links

  Link to State Geological Map from USGS.  Link to Massachusetts Geological Survey.

• Other

Click here for an explanation of categories and illustrations